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gvisor/test/syscalls/linux/proc_net_tcp.cc

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// Copyright 2019 Google LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
#include "gtest/gtest.h"
#include "gtest/gtest.h"
#include "absl/strings/numbers.h"
#include "absl/strings/str_join.h"
#include "absl/strings/str_split.h"
#include "test/syscalls/linux/ip_socket_test_util.h"
#include "test/util/file_descriptor.h"
#include "test/util/test_util.h"
namespace gvisor {
namespace testing {
namespace {
using absl::StrCat;
using absl::StrSplit;
constexpr char kProcNetTCPHeader[] =
" sl local_address rem_address st tx_queue rx_queue tr tm->when "
"retrnsmt uid timeout inode "
" ";
// TCPEntry represents a single entry from /proc/net/tcp.
struct TCPEntry {
uint32_t local_addr;
uint16_t local_port;
uint32_t remote_addr;
uint16_t remote_port;
uint64_t state;
uint64_t uid;
uint64_t inode;
};
// Finds the first entry in 'entries' for which 'predicate' returns true.
// Returns true on match, and sets 'match' to a copy of the matching entry. If
// 'match' is null, it's ignored.
bool FindBy(const std::vector<TCPEntry>& entries, TCPEntry* match,
std::function<bool(const TCPEntry&)> predicate) {
for (const TCPEntry& entry : entries) {
if (predicate(entry)) {
if (match != nullptr) {
*match = entry;
}
return true;
}
}
return false;
}
bool FindByLocalAddr(const std::vector<TCPEntry>& entries, TCPEntry* match,
const struct sockaddr* addr) {
uint32_t host = IPFromInetSockaddr(addr);
uint16_t port = PortFromInetSockaddr(addr);
return FindBy(entries, match, [host, port](const TCPEntry& e) {
return (e.local_addr == host && e.local_port == port);
});
}
bool FindByRemoteAddr(const std::vector<TCPEntry>& entries, TCPEntry* match,
const struct sockaddr* addr) {
uint32_t host = IPFromInetSockaddr(addr);
uint16_t port = PortFromInetSockaddr(addr);
return FindBy(entries, match, [host, port](const TCPEntry& e) {
return (e.remote_addr == host && e.remote_port == port);
});
}
// Returns a parsed representation of /proc/net/tcp entries.
PosixErrorOr<std::vector<TCPEntry>> ProcNetTCPEntries() {
std::string content;
RETURN_IF_ERRNO(GetContents("/proc/net/tcp", &content));
bool found_header = false;
std::vector<TCPEntry> entries;
std::vector<std::string> lines = StrSplit(content, '\n');
std::cerr << "<contents of /proc/net/tcp>" << std::endl;
for (const std::string& line : lines) {
std::cerr << line << std::endl;
if (!found_header) {
EXPECT_EQ(line, kProcNetTCPHeader);
found_header = true;
continue;
}
if (line.empty()) {
continue;
}
// Parse a single entry from /proc/net/tcp.
//
// Example entries:
//
// clang-format off
//
// sl local_address rem_address st tx_queue rx_queue tr tm->when retrnsmt uid timeout inode
// 0: 00000000:006F 00000000:0000 0A 00000000:00000000 00:00000000 00000000 0 0 1968 1 0000000000000000 100 0 0 10 0
// 1: 0100007F:7533 00000000:0000 0A 00000000:00000000 00:00000000 00000000 120 0 10684 1 0000000000000000 100 0 0 10 0
// ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^
// 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
//
// clang-format on
TCPEntry entry;
std::vector<std::string> fields =
StrSplit(line, absl::ByAnyChar(": "), absl::SkipEmpty());
ASSIGN_OR_RETURN_ERRNO(entry.local_addr, AtoiBase(fields[1], 16));
ASSIGN_OR_RETURN_ERRNO(entry.local_port, AtoiBase(fields[2], 16));
ASSIGN_OR_RETURN_ERRNO(entry.remote_addr, AtoiBase(fields[3], 16));
ASSIGN_OR_RETURN_ERRNO(entry.remote_port, AtoiBase(fields[4], 16));
ASSIGN_OR_RETURN_ERRNO(entry.state, AtoiBase(fields[5], 16));
ASSIGN_OR_RETURN_ERRNO(entry.uid, Atoi<uint64_t>(fields[11]));
ASSIGN_OR_RETURN_ERRNO(entry.inode, Atoi<uint64_t>(fields[13]));
entries.push_back(entry);
}
std::cerr << "<end of /proc/net/tcp>" << std::endl;
return entries;
}
TEST(ProcNetTCP, Exists) {
const std::string content =
ASSERT_NO_ERRNO_AND_VALUE(GetContents("/proc/net/tcp"));
const std::string header_line = StrCat(kProcNetTCPHeader, "\n");
if (IsRunningOnGvisor()) {
// Should be just the header since we don't have any tcp sockets yet.
EXPECT_EQ(content, header_line);
} else {
// On a general linux machine, we could have abitrary sockets on the system,
// so just check the header.
EXPECT_THAT(content, ::testing::StartsWith(header_line));
}
}
TEST(ProcNetTCP, EntryUID) {
auto sockets =
ASSERT_NO_ERRNO_AND_VALUE(IPv4TCPAcceptBindSocketPair(0).Create());
std::vector<TCPEntry> entries =
ASSERT_NO_ERRNO_AND_VALUE(ProcNetTCPEntries());
TCPEntry e;
ASSERT_TRUE(FindByLocalAddr(entries, &e, sockets->first_addr()));
EXPECT_EQ(e.uid, geteuid());
ASSERT_TRUE(FindByRemoteAddr(entries, &e, sockets->first_addr()));
EXPECT_EQ(e.uid, geteuid());
}
TEST(ProcNetTCP, BindAcceptConnect) {
auto sockets =
ASSERT_NO_ERRNO_AND_VALUE(IPv4TCPAcceptBindSocketPair(0).Create());
std::vector<TCPEntry> entries =
ASSERT_NO_ERRNO_AND_VALUE(ProcNetTCPEntries());
// We can only make assertions about the total number of entries if we control
// the entire "machine".
if (IsRunningOnGvisor()) {
EXPECT_EQ(entries.size(), 2);
}
EXPECT_TRUE(FindByLocalAddr(entries, nullptr, sockets->first_addr()));
EXPECT_TRUE(FindByRemoteAddr(entries, nullptr, sockets->first_addr()));
}
TEST(ProcNetTCP, InodeReasonable) {
auto sockets =
ASSERT_NO_ERRNO_AND_VALUE(IPv4TCPAcceptBindSocketPair(0).Create());
std::vector<TCPEntry> entries =
ASSERT_NO_ERRNO_AND_VALUE(ProcNetTCPEntries());
TCPEntry accepted_entry;
ASSERT_TRUE(FindByLocalAddr(entries, &accepted_entry, sockets->first_addr()));
EXPECT_NE(accepted_entry.inode, 0);
TCPEntry client_entry;
ASSERT_TRUE(FindByRemoteAddr(entries, &client_entry, sockets->first_addr()));
EXPECT_NE(client_entry.inode, 0);
EXPECT_NE(accepted_entry.inode, client_entry.inode);
}
TEST(ProcNetTCP, State) {
std::unique_ptr<FileDescriptor> server =
ASSERT_NO_ERRNO_AND_VALUE(IPv4TCPUnboundSocket(0).Create());
auto test_addr = V4Loopback();
ASSERT_THAT(
bind(server->get(), reinterpret_cast<struct sockaddr*>(&test_addr.addr),
test_addr.addr_len),
SyscallSucceeds());
struct sockaddr addr;
socklen_t addrlen = sizeof(struct sockaddr);
ASSERT_THAT(getsockname(server->get(), &addr, &addrlen), SyscallSucceeds());
ASSERT_EQ(addrlen, sizeof(struct sockaddr));
ASSERT_THAT(listen(server->get(), 10), SyscallSucceeds());
std::vector<TCPEntry> entries =
ASSERT_NO_ERRNO_AND_VALUE(ProcNetTCPEntries());
TCPEntry listen_entry;
ASSERT_TRUE(FindByLocalAddr(entries, &listen_entry, &addr));
EXPECT_EQ(listen_entry.state, TCP_LISTEN);
std::unique_ptr<FileDescriptor> client =
ASSERT_NO_ERRNO_AND_VALUE(IPv4TCPUnboundSocket(0).Create());
ASSERT_THAT(RetryEINTR(connect)(client->get(), &addr, addrlen),
SyscallSucceeds());
entries = ASSERT_NO_ERRNO_AND_VALUE(ProcNetTCPEntries());
ASSERT_TRUE(FindByLocalAddr(entries, &listen_entry, &addr));
EXPECT_EQ(listen_entry.state, TCP_LISTEN);
TCPEntry client_entry;
ASSERT_TRUE(FindByRemoteAddr(entries, &client_entry, &addr));
EXPECT_EQ(client_entry.state, TCP_ESTABLISHED);
FileDescriptor accepted =
ASSERT_NO_ERRNO_AND_VALUE(Accept(server->get(), nullptr, nullptr));
const uint32_t accepted_local_host = IPFromInetSockaddr(&addr);
const uint16_t accepted_local_port = PortFromInetSockaddr(&addr);
entries = ASSERT_NO_ERRNO_AND_VALUE(ProcNetTCPEntries());
TCPEntry accepted_entry;
ASSERT_TRUE(FindBy(entries, &accepted_entry,
[client_entry, accepted_local_host,
accepted_local_port](const TCPEntry& e) {
return e.local_addr == accepted_local_host &&
e.local_port == accepted_local_port &&
e.remote_addr == client_entry.local_addr &&
e.remote_port == client_entry.local_port;
}));
EXPECT_EQ(accepted_entry.state, TCP_ESTABLISHED);
}
} // namespace
} // namespace testing
} // namespace gvisor
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